Do they need to log in or is it possible to share a link, where they can answer questions anonymously? Does Rumble collect and select the answers?
You have 3 different ways to invite guests in your "3. Share" tab:
1) Share a link of the interview generated by Rumble Studio to your guest (ready for a tweet or an email).
2) Share a QR code generated by Rumble studio.
3) Get a code to embed your interview on your website.
All they need to do is sign up with their email id (so you can identify who has answered what), and you have the freedom to choose the answers that you need for your podcast.